How do I place the building footprint areas properly in the block(parcel) area ?

[MikeJane]

   Hello, I want to put a lot of buildings in a large parcel area. However, there should be some distances between the buildings and no buildings overflowing outside the parcel area.(Like in the attached png.)

   How do I create a rule, I'm new to writing rules. Can you help me with the method?

[CherylLau · Accepted solution]

You can split your parcel shape into a grid of building footprints and use geometry.isRectangular to discard the ones that are not rectangular.

Parcel -->
	split(x) { { ~spacing: NIL
			   | width: ParcelSlice }*
			 | ~spacing: NIL }
			 
ParcelSlice -->
	split(z) { { ~spacing: NIL
			   | width: TestFootprint }*
			 | ~spacing: NIL }

TestFootprint -->
	case geometry.isRectangular(0.1):
		Footprint.
	else:
		NIL
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https://doc.arcgis.com/en/cityengine/latest/cga/cga-split.htm

https://doc.arcgis.com/en/cityengine/latest/cga/cga-geometry-function.htm#ESRI_SECTION1_7DBA4E7E8618...

If you want an aligned grid, use the noAdjust option in the split.